Jack Casey was born in Liverpool. A school teacher, he played as an amateur for Bromley between 1908-1911. During this period the team won the Spartan League, the Isthmian League (twice) and the FA Amateur Cup.
An outside-left, Jack Casey joined West Ham United and made his debut against Gillingham on 2nd November 1912. West Ham began a good run of form in January 1913 and a team that included Casey, George Hilsdon, Dan Bailey, Fred Harrison, George Butcher, Herbert Ashton and Albert Denyer, went through the rest of the season unbeaten. This included 7 games won and 8 games drawn. Casey ended up the season with 3 goals in 24 games. However, he was never a great goalscorer and only got 2 goals in 19 games.